Gas turbines typically include various metallic components that sustain damage during operation of the gas turbine. This is particularly true for metallic components formed from thin metallic plates that include a plurality of through-holes. For instance, combustion cap effusion plates used in combustion chamber assemblies often sustain damage such as cracks or fractures due to the dynamic loading resulting from combustion in a combustion chamber assembly. It is desirable to repair such damage without having to replace the entire metallic component.
Previously, weld repair of such damage using standard MIG (metal inert gas) or TIG (tungsten inert gas) welding techniques has been performed with limited success. The higher heat effects resulting from MIG or TIG welding processes often lead to crack propagation and difficulty in containment of damage. For instance, the heat affected zone generated by such MIG and TIG welding techniques often overlaps into the undamaged area of the effusion plate, which can lead to more damage.
Brazing processes are also known for repairing damage to metallic components of a gas turbine. Brazing is typically more successful than MIG or TIG welding. However, brazing is much more expensive and time consuming due to the necessary cleaning and brazing furnace cycles. Moreover, it is often difficult to perform the brazing techniques in situ, making convenient and timely repair of damaged articles more difficult.
Accordingly, a process for repairing metallic components of gas turbines that addresses at least certain of the present disadvantages associated with MIG/TIG welding and brazing would be useful.